Duplex tone arm



June 16, 1942.

C. A. VOLF DUPLELTONE ARM Filed March 25, 1941 2 Sheets-Sheet 1 ilbtomw June 16, 1942. c. A. VOLF DUPLEX TONE ARM Filed March 25, 1941 2 Sheets-Sheet 2 w v a Patented June 16, 1942 DUPLEX TONE ARM Christian A. V011, Van Nuys, CaliL, assignor to Clarence W. Sinn, New York, N. Y.

Application March 25, 1941, Serial No..385,162 8 Claims. (01. 274-23) This invention relates to sound recording and reproduction. The instrument embodying the elements of the invention provides means for recording sound on or reproducing sound from a plurality of records.

One of the objects of the invention is to incorporate a push-pull principle in a plurality of sound heads mounted on a tone arm to reduce surface noise of the phonograph needle in riding against one side of the groove on a record.

Similarly, a conversational record maybe reproduced simultaneously with a record having other accompanying sounds, such as those of birds, insects, whistles and the like, and a composite record made of the recordings of both of the first records.

As another example of the use of the device,

' in an orchestral reproduction two blank records Another object of the invention is toprovide 1 means whereby sounds may be recorded or reproduced on a plurality of records to effect a composite result found useful in a number of professions, including the teaching and medical.

Other objects of the invention will become apparent from a careful study of the hereunto annexed specification and drawings, in which drawings:

Fig. 1 is a top plan view of the double arm assembly inoperative position over two records;

Fig. 2 is a side elevation of the instrument shown in Fig. 1; g

Fig. 3 is a cross section of details of the central pivot and elevating means for. the tone arm as'- sembly;

Fig. 4 is a sectional view similar to Fig. 3, taken at right angles to the latter;

Fig. 5 is a perspective view of a detail of the device to limit movement between the two sections of the tone arm;

Fig. 6 is a schematic diagram showing two record holders operated by a single motor; and

Fig. '7 is a schematic diagram showing two record holders each driven by an independent motor.

The essence of this invention comprises the phonograph recording or reproducing arm of a duplex type. A composite pivoted arm is provided which has a sound head mounted at either end of the arm, the heads being readily replaced by either a sound recording or'reproducing head, depending on what is desired at each end of the arm.

Refinements are incorporated in the structure which permit adjustments of several kinds that will be described later, which permit the structure to be utilized advantageously in the following respects.

By using the instant invention it is possible to reproduce two difierent kinds of special sounds simultaneously, such as a vocal solo on one record and an orchestral accompaniment on another record, and from the two reproductions a composite record may be made on a third record.

may be utilized, one beneath each of the sound heads which, in this instance, will be recording heads, and one head will be made responsive particularly to low notes or to a special group of instruments andthe other head will be set responsive particularly to high notes or a stilldifierent special set of instruments. 'The two records thus made may then be played simultaneously in a twin reproducer of the character of this device and this simultaneous playing may be broadcast as a composite selection or the simultaneous playing may be recorded on a third record for future playing or broadcast. One object for this is that it has been proven that the difference in volume obtained from two records feeding into one amplifier is increased approximately 5 to 10 decibels over the summation of the sound from two individual records not played simultaneously, and the distinctness and separation ofthe musical scores and voices will be reproduced with greater record holder of the applicant's device'and a reproducing head fitted to cooperate with this record, while on the other record holder ablank record is provided and 'a recording head fixed to the corresponding end of the tone arm so that a pupil may sing into an independent microphone,

the blank record recording both the orchestral selection and the voice of the pupil.

In this connection it is possible to arrange the applicants device whereby the voice may be recorded independently rather than having a composite record of voice and orchestra both, in which instance corrections may be made in the record being made of the voice and the record on which the recording is made may be played back, using the twin phonograph arm, on replayingi to determinewhether the mistake has been satisfactorily'corrected. I

Still another, important use of applicants inventiofi is found in instructing the deaf, with a view toward improving their natural-hearing, particularly where such teaching is done in classes through a sound source. In order that a same connectionvarious combinations of overtones, harmonics and independent combinations ofsound on a single record may be formed into a composite result which may be added to or detracted from by the exchange of 1 records to suit the-particular progress that the deaf patient has reached at the particular time of treatment, and as their hearing improves from time to time, another combination of these sounds may be made by suitable combinations of the proper records.

This is brought about by the fact that 1: the needle inone end of the arm tends to push I against one side of the groove, the needle on the opposite end of the arm will have a drag impressed on'it by such pushing and thus tend to bring the first needle back to the center of the groove.

As shown in Figs. 1 and 2, a composite tone arm Ill ispivotally mounted about a standard H, the details of the pivoting means comprising a tubular member |2 secured to the arm Ill.

- A cam I3 is pivotally mounted in the upper end V In further explanation of this,-for instance, a

record is formed having a train whistle. A train gwhistle is heard bypeople with'normal hearing in combinatiom; lth many other sounds,.such as .a locomotive or 'oving and any reverberated soundsithat'arecreated by the movement of the train. To a deaf person it is of distinct value to bring about the ability to understand all or these independent sounds in combination with one another andv gradually learn to discriminate between them all. In the .earlier treatment only. a very few of the basic noises are used, whereas its treatment progresses, more complex combinations of these noises are brought 'into play and a-wide range of possibilities of the combination of such noises is permitted by using the instant invention, together with suitable recbids for the purpose.

In passing, it might be I said that the applicant has provided a device that has wide possibilities in aifording treatment for improving the hearing of deaf or partially Y deaf persons and has providedsubstantially thir-.

ty diflerentcompositions of records which are "available for prescriptions in treating such per- 1 the treatment eiIected byiusing the device, and

therefore a more -detaile mechanism followsi GM of the importan a description. cf .the dvantages. of f record; gInaf-theapplicantsdevice this is offset puny pr neip1e;v.1;1'he rec ordholders are-rotatably mounted; tin-"pivots the" pivot for, jthe "tone arm is substantiallyfinfline with these two pivots.

vention resides ing the i ,reduction of the surface noise .:of the' phonographneedle proper. which tends to ridejagainsti oneside of thegroove of the of the tubular member |2 about a pivot H. A concave seat I5 is provided at the top of the standard II and a ball bearing l6 is seated therein. The surface of the'cam l3 engages the ball bearing to raise and lower the tubular member l2 and tone arm aiflxed thereto.

Surrounding the tubular member I2 is a cylindrical element l'l which is flxed'to the standard II by means of a threaded lug ll. The tubular member l2 and the arm may move vertically with respect to the standard II and the cylindrical element since a slot I8 is provided in the tubular member |2 in which the threaded lu l8 may move.

The tone arm I0 is actually composed of two 25 at one end. The opposite end of resilient member 24 is formed generally as an annulus to provide a loop 28 surrounding the cylindrical element II. The inner diameter of the loop 28 is larger than the outer diameter of the cylindrical element I1, whereby a limited amount of movement may be afforded the arm 2| about the pivot 22.

The outer end of the loop 26 is formed with an element having a depending notch 21 which engages lug I8. The amount of play afforded the resilient member 24 is controlled by the threaded screw 28.

To summarize the operation up to thispoint, when the cam I3 is swung to the position .of Fig. 4, both parts .20 and 2|: of the duplex tone arm are raised, and are ,heldin the raised position by the locking action of the cam; at the same time, loop 21 is raised into engagement with pin I respective records. Swinging the cam over 180 lowers member l2, whichjlowerstone arm 20 and inasmuch as tone arm 2| is supported by tom: 20, on pivot 22, tone arm 2| is simultaneously lowered, and loop 21 disengaged. This gives arm. v

The tone arm is arranged-crosswise of the line of Y v pivots, whereby "as,the' head onone endof them arm is fed inwardly, the head on thelother. end

, of the armwillalso be fed inwardly on the T otherv record, andin the feeding of the needles 1 inwardly, th ends of the armswill impress sub stantially the same identical drag uponeach oth-- er while the needles are in the grooves, tocause :more flexibility in balance between the two a ms.

sitioned in its sound groove.

2|, a slight freedom of movement with respect to arm 20, so that each arm can be accurately po- Aflixed to the outer end of each of the parts '20 and 2| ofthe arm llli's a hinge 29 and the opposite end of the hinge 30 is secured to a hous- .ing '3 which-housing is. adapted to receive and securely retain a sound head 32, the head carrying the usual wiring, needle and the like. The

head may besecured withinthe housing by any suitable means such as a screw 33.

against the record groove through 'the medium of the needle may be -readily and suitably varied. The sound heads 32 may be either recording or reproducing and it is readily apparent-that a recording head maybe afllxed toone'end of the .arm while a reproducing head may be fixed to the other end, or both heads 'may befrecording or reproducing heads, as desired. j

' Record holders'38 each support arecord' 39, the record holders being driven as shown in Fig. 6 in the same rotary direction by means of1a constant speed motor, 40 having a double ended shaft with worm and gear driving means 4| con:- necting the motor to the record holders. 'I'he speed of the motor, however, may be varied if desired by .a suitable control 42 such asa rheostat.

If it is desired to drive the record holders at different speeds, a schematic diagram is shown in Fig. 7, whereby a separate motor 4| may be provided to drive each record holder, these inotors also having suitable speed control means 42 arranged in their power circuits.

When the cam is in the position shown in Fig. 4, the tone arm assembly including the sound heads, is in elevated or inactive position. That is, the needles are not in registry with the grooves of the records. When, however, the cam is in the position opposite to that in Fig. 4, that is, has been turned 180 to said position, the tone arm assembly will be in lowered or record-engaging position. Thus the device readily lends itself to rapid manipulation by this feature. Furthermore, in order that the proper point for starting each recordmay be readily reached, the moving of arm part 2| with respect to part 20 will permit the operator to place the needle at the exact desired location on each record.

When it is desired to use only one sound head, the other sound head may be pivoted 180 about the pivoted hinge 29 to rest on top of the tone arm; the other sound head may be used in'this.

connection as a single arm arrangement.

As a modification of the instant invention, the

same is notlimited to one tone arm assembly, but maybe incorporatedwithiri reasonable limitsto embody more than one and, for example two, comprising two assemblies of two heads each. Such two arm assemblies may be provided on the same central standard. This would necessitate using alittle longer arm than that illustrated andv in this event one arm assembly comprising asingle assembly will be slightly above 'the level of the arm which comprises a second assembly. Such an arrangement will serve to conserve space. The four record olders may be rotated, for example, by gearing the additional two record holders to the periphery of the first two, in order to maintain identical speeds of the four tables. The various pick-up or recording heads in the latter set-up can be independently controlled by turning them backwards or to rest positions on the tone arms if they are not all to be worked at the same time.

' pended claims.

through the arm pivot Il' to influence the other end of the tone arm and its corresponding nee die to keep the'latter in the center of the groove in its corresponding record. Similarly, said otherneedle, in riding in thegroove in its record and in staying in the center thereof, will transmit force through the arm pivot to act onthe first needle to tend to keep it in the center of the groove of its-corresponding record. Thus, needle scratch is reduced and an equalization feature is induced which is described as having apus'h-pull principle.

Having thus described theinvention, it is to be understood that changes may be made in carrying outthe invention without departing from the spirit thereof and the invention is to be limited only insofar as warranted by the ap- I claim: i. .A duplex. tone arm'for simultaneous cooperation with a pair of sound records of the disc type .positioned on side ,by side driving tables, comprising a supporting standard positioned between said tables', a tone arm carried by said standard, a second tone arm, supported by the firsttone'arm, sound translating devices at the ends of each of said tone arms, and means,

forming part of said supporting standard, for lowering and raising the first tone arm, and with it, the second tone arm, into and out-of operative relationship with their respective records.

2. A duplex tone arm for simultaneous cooperation with a pair of sound records of the disc type positioned on side by side driving tables, comprising a supporting standard positioned between said tables, a tone arm carried by said standard, a second tone arm, movably supported by the first tone arm to have a slight degree of freedom of movement with respect thereto, sound translating devices at the ends of each of said -tone arms, and means, forming part of said supporting'standard, for lowering disc type positioned on side by side driving tables, comprising a supporting standard positioned between said tables, a tone arm carried by said standard, a second tone arm, pivotally supported by the first tone arm on a vertical axis, to have a slight degree of freedom of movement with respect thereto, sound translating devices at the ends of each 01' said tone arms, and means, forming part of .said supporting standard, for lowering and raising the first tone arm, and with it, the second tone am, into and out of operative relationship with their respective records.

4. A duplex tone arm for simultaneous cooperation with a pair of sound records of the disc type positioned on side by side driving table's, comprising a supporting standard positioned between said tables, a tone arm carried by said standard, a second tone arm supported by the first tone arm, sound translating devices at the ends of each of said tone arms, means, forming part of said supporting standard, for lowering and raising the first tone arm, and with it, the second tone arm, into and out of operative relationship with their respective records, and latching means, operative to latch the tone arms together when in raised position, and to release said arms from such latching engagement when the arms are lowered. 5. A duplex tone arm for simultaneous cooperation with a pair of sound records of the.

disc type positioned on side by side driving tables comprising a supporting standard positioned between said tables, a tone arm carried by said standard, a second tone arm supported by the first tone arm, sound translating devices at the ends of each of said tone arms, and means, forming part of said supporting standard, and including a manually operated cam, operatively connected to the first tone arm, for lowering and raising the first tone-arm, and with it, the second tone arm, into and out of operative relationship with their respective records.

6. A duplex tone arm for simultaneous cooperation with a pair of sound records of the disc type positioned on side by side driving tables, comprising a supporting standard positioned between said tables, a tone arm carried by said standard, a second tone arm supported by the first tone arm, sound translating devices pivotally mounted on the ends of the tone arms, and swingable into and out of operative relation with their respective records, and means, forming part of said supporting standard, for lowering and raising the first tone arm, and with it,

the second tone arm, into and out of operative relationship with their respective records.

7. A duplex tone arm for simultaneous cooperation with a pair of sound records of the disc type positioned on side by side driving tables,

comprising a supporting standard positioned between said tab1es,,a tone arm carried by said standard, a second tone arm supported by the first tone arm, sound translating devices each provided with a counterweight, and swingable on horizontal pivots, into and out of operative relation with theirrespective records, and means,

of said devices being variably positionable longitudinally on its tone arm, and means, forming part of said supporting standard, for lowering and raising the first tone arm, and with it, the second tone arm, into and out of operative relationship with their respective records.

CHRISTIAN A. VOLF. 

